The invention relates to a device for regenerating an ion exchange cartridge which is provided with an inlet and an outlet.
Tap water is heated in domestic appliances such as steam irons, coffee makers and electric kettles. A quantity of CaCO3 and MgCO3 is deposited in the heating process, depending on the hardness of the water. The deposit thus formed is referred to as scale. A scale deposit gives rise to inter alia an impaired heat transfer and choking-up of water duct systems, and in the end to a premature failure of the domestic appliance. To counteract scale depositions, it is known, for example in electric irons, to use so-called anti-scale cassettes or cartridges. Such cartridges usually contain a resin which binds the alkaline earth metal ions among them Ca2+ and Mg2+, but also, for example, CO32xe2x88x92, when coming in to contact with the water, so that no scale is formed. These cartridges are to be replaced with fresh cartridges from time to time, depending on the hardness of the water.
It is an object of the invention to provide a device with which the user of the domestic appliance him/herself can regenerate the cassette or cartridge in a simple manner, i.e. with which the alkaline earth metal ions can be removed from the cartridge, so that the cartridge can be re-used and need not be discarded.
The device according to the invention is for this purpose characterized in that the device is provided with a reservoir for the accommodation of a solution in which alkali metal ions and chloride ions are present, which reservoir is provided with an outlet to which the inlet of the ion exchange cartridge can be connected. The user takes the ion exchange cartridge from the domestic appliance and connects it with its inlet to the outlet of the reservoir of the regeneration device. Then the reservoir is filled with a solution in which alkali metal ions and chloride ions are present. After the reservoir has been filled, the solution (or brine) flows into the ion exchange cartridge, with the result that the alkaline earth metal ions from the resin of the ion exchange cartridge are replaced by the alkali metal ions of the solution. Such a solution may consist, for example, of water in which a quantity of ordinary salt (NaCl) has been dissolved. The required quantity of salt, equal to the product of the volume (L) and the concentration (g/L), must be sufficient. This obviously depends on the size of the cartridge. The solution flowing from the cartridge and the reservoir may be caught, for example, in a kitchen sink. The regeneration device is a comparatively simple tool by means of which a user him/herself can make the cartridge ready for use again. Any (bi)carbonate and sulfate (possibly sulfite) ions present in the ion exchange cartridge, such as CO32xe2x88x92 or HCO3xe2x88x92 and SO42xe2x88x92 or SO32xe2x88x92, are exchanged with the Clxe2x88x92 ions from the salt solution at the same time. It may be noted that the regeneration process is known per se from industrial applications.
A preferred embodiment of the device is characterized in that the device is provided with a chamber in which the ion exchange cartridge can be placed, which chamber is provided with an inlet and an outlet, said inlet of the chamber being connected to the outlet of the reservoir, while said inlet and outlet of the chamber are coupled to the inlet and outlet, respectively, of the cartridge when a cartridge is inserted. The chamber facilitates the placement of the cartridge in the device.
A further preferred embodiment of the device is characterized in that a restriction is present in the flow path of the solution situated between the outlet of the reservoir and the outlet of the chamber. The flow velocity of the solution through the cartridge can be adjusted thereby such that an optimum regeneration rate is obtained. The restriction may be, for example, a spring-loaded non-return valve.
A yet further embodiment is characterized in that the outlet of the reservoir lies at a higher level than the outlet of the chamber in the operational condition of the device. The reservoir will empty itself completely under the influence of the hydrostatic pressure.
In yet another embodiment, a filter is present in the flow path of the solution situated between the outlet of the reservoir and the inlet of the chamber. This prevents any impurities, which could adversely affect the operation of the ion exchange cartridge, from entering this cartridge.